Preliminary spectrum of genetic variants in familial hypercholesterolemia in Argentina

Highlights: - First description of familial hypercholesterolemia mutations in Argentina; - Identification of 7 patients with severe familial hypercholesterolemia; - Wide genetic heterogeneity with 1 relatively common allele, the Lebanese mutation; Description and deep bioinformatics characterization of 4 novel genetic variants; - Studying the exon 14 in a first step could be a low-cost approach for this population. Background: Familial hypercholesterolemia (FH) is a genetic disorder characterized by elevated low-density lipoprotein cholesterol and early cardiovascular disease. As cardiovascular disease is a leading cause of mortality in Argentina, early identification of patients with FH is of great public health importance. Objective: The aim of our study was to identify families with FH and to approximate to the characterization of the genetic spectrum mutations of FH in Argentina. Methods: Thirty-three not related index cases were selected with clinical diagnosis of FH. Genetic analysis was performed by sequencing, multiplex ligation-dependent probe amplification, and bioinformatics tools. Results: Twenty genetic variants were identified among 24 cases (73%), 95% on the low-density lipoprotein receptor gene. The only variant on APOB was the R3527Q. Four were novel variants: c.-135C>A, c.170A>C p.(Asp57Ala), c.684G>C p.(Glu228Asp), and c.1895A>T p.(Asn632Ile); the bioinformatics’ analysis revealed clear destabilizing effects for 2 of them. The exon 14 presented the highest number of variants (32%). Four variants were observed in more than 1 case and the c.2043C>A p.(Cys681*) was carried by 18% of index cases. Two true homozygotes, 3 compound heterozygotes, and 1 double heterozygote were identified. Conclusion: This study characterizes for the first time in Argentina genetic variants associated with FH and suggest that the allelic heterogeneity of the FH in the country could have 1 relative common low-density lipoprotein receptor mutation. This knowledge is important for the genotype–phenotype correlation and for optimizing both cholesterol-lowering therapies and mutational analysis protocols. In addition, these data contribute to the understanding of the molecular basis of FH in Argentina.

Keywords

APOB Argentina Cardiovascular Disease Cardiovascular Disease Prevention Cholesterol Familial Hypercholesterolemia Genetic Variants LDLR gene Mutations Public Health Doenças Cardio e Cérebro-vasculares